Frontiers in Microbiology (Aug 2018)

Further Elucidation of Galactose Utilization in Lactococcus lactis MG1363

  • Ana Solopova,
  • Herwig Bachmann,
  • Bas Teusink,
  • Jan Kok,
  • Oscar P. Kuipers

DOI
https://doi.org/10.3389/fmicb.2018.01803
Journal volume & issue
Vol. 9

Abstract

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Since the 1970s, galactose metabolism in Lactococcus lactis has been in debate. Different studies led to diverse outcomes making it difficult to conclude whether galactose uptake was PEP- or ATP- dependent and decide what the exact connection was between galactose and lactose uptake and metabolism. It was shown that some Lactococcus strains possess two galactose-specific systems – a permease and a PTS, even if they lack the lactose utilization plasmid, proving that a lactose-independent PTSGal exists. However, the PTSGal transporter was never identified. Here, with the help of transcriptome analyses and genetic knock-out mutants, we reveal the identities of two low-affinity galactose PTSs. A novel plant-niche-related PTS component Llmg_0963 forming a hybrid transporter Llmg_0963PtcBA and a glucose/mannose-specific PTS are shown to be involved in galactose transport in L. lactis MG1363.

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